1. Field of the Invention
The present invention relates to a lockable slider for slide fasteners wherein the slider can be readily switched between a locked disposition and an unlocked disposition by manipulating a simple locking mechanism.
2. Description of the Related Art
Several sliders of the type mentioned above are known, an example of which is a lockable slider as disclosed for instance in U.S. Pat. No. 5,167,052 and another example is a lockable slider as taught in U.S. Pat. No. 2,261,132.
The slider shown in the first-named application comprises a slider body having a neck portion provided at the front end thereof and having a channel to reciprocate rows of coupling elements, a locking member having a locking prong formed at its one end and adapted for oscillation to bring the locking prong into and out of the coupling element reciprocation channel, and a rotatable actuating roller or integral actuating lever movably disposed on the neck portion and connected cooperatively to the locking member, the actuating lever projecting outwardly for manipulation from outside of the slider. The locking member employed in such a prior art slider is structurally complicated and literally tedious to manipulate. Furthermore, this locking member cannot attain reliable locking or unlocking operation of the slider relative to the coupling element rows. Because of the disposition of the locking member on the slider body, moreover, the slider is rather bulky and less aesthetic.
In the last-named patent, the slider is composed of a slider body having therein a longitudinally disposed channel for slidably guiding rows of coupling elements, a pull member pivoted to the slider body, locking means disposed on the pull tab and adapted to move into and out of the guide channel by a swinging movement of the pull tab, cam means on the pull member having a plurality of flat surfaces defining unlocked and locked positions of the pull member and the locking member, and a leaf spring carried by the slider body and engaging the cam means and cooperating with the flat surfaces thereof. The leaf spring yieldingly urges the pull member to the nearest of a plurality of predetermined positions defined by the flat surfaces of the cam means from positions between those predetermined positions, and yieldingly maintains the pull member in such predetermined positions for locking and unlocking the slider. This known slider is arranged such that the locking member integral with the pull member is retracted from the guide channel by pulling the pull member in one or the other direction and is brought into engagement in between the coupling elements by flipping the pull member flat against the slider body. Since the locking and unlocking operation of the slider can be done by simple manipulation of the pull tab, the slider tends to accidentally release from its locked position and hence would not warrant application for security purposes.